[ncmncm]

Batteries just cost more than alternatives. They are excellent for load smoothing, because they can vary power intake and output very quickly, at any wattage out, but they are an expensive place to keep energy. For home use, batteries are the only practical storage we have, which is why off-grid power is much costlier than utility scale need be.

Battery cost is per Wh of total capacity, with typically a very high limit of W in or out. Alternatives mostly cost, instead, per W of power in or out, with an increase of total Wh stored costing relatively little, mainly limited by convenience.

For example, pumped hydro. The expensive part is the turbine. (You often don't even need a dam.) Want more watts, you need another turbine; but you can usually pump up way more water than you will need.

Likewise, synthetic ammonia or hydrogen, or liquified nitrogen or compressed air. Tankage is super-cheap, but electrolysers, cryo units, and compressors cost, as do turbines. More watts out means more turbines, again.

For buoyancy storage, the floats, sea-floor pulleys, cable reels, and clutches are cheap, the size or number of winch motor / generators determines how many watts you can put in or get out. Similarly for mineshaft gravity storage: The 10,000 ton weight is cheap, and the mineshaft has plenty of depth. Wattage is in the winch.

Producing enough lithium batteries for both cars and utilities would put a serious strain on world capacity to mine lithium. It is better reserved mainly for cars, where its light weight matters. Where you do want batteries, other chemistries are likely better for utilities than fought-over lithium. I expect molten metal batteries to be competitive soon.

It is strange that most people who talk about storage seem to have no conception of what makes a thing more, or even prohibitively, expensive. Thus, Energy Vault has a $2B market cap for a system that is very obviously totally useless. People propose putting expensive electromechanical equipment on the sea floor. The storage that will be used will be the storage that is cheap to buy and cheap to use.

[epistasis]

Batteries are getting cheaper all the time as we get better at manufacturing them, and we haven't hit the inflection point on cost decreases yet, and we haven't scaled lithium production yet. And we haven't fully developed other chemistries such as iron-air that promise to be even cheaper than lithium ion and have far higher capacity/power ratios.

Chemical storage of energy is highly inefficient, which is fine when we have super super cheap energy, but the capital costs of conversion and storage will probably require nearly continuous usage of the, say, electrolyzers in order to make the storage project feasible.

Perhaps you are right, and I really appreciate you laying out your reasoning, but I would bet otherwise about grid storage! None of the players for doing alternatives are anywhere near market ready, and batteries are being deployed today. As they get cheaper they will be deployed even more.

[ncmncm]

Batteries are also chemical storage, but I guess you mean synthetic fuels. Their cheap tankage, easy transportability, and ready sale value forgive a great deal of inefficiency. If not drawn down every night, efficiency hardly matters. Overnight storage wants efficiency and unlimited cycles. But transmission lines will probably end up preferred where available.

Buoyancy storage, where deep water is ready to hand, and mineshaft storage, where you have one, will be very, very cheap and efficient. Transmission lines mean such conveniences need not be especially nearby. But Europe is absolutely perforated with mineshafts.

Besides smoothing, there is very little use for storage yet, because we haven't got enough to charge it from. Charging storage from NG turbines would be worse than silly. So, we build out generating capacity first, then storage.